Indian youth living on reservations have very high levels of drug involvement, perhaps the highest of any ethnic group. National data sources adequately monitor drug use among non-Indians, but either do not assess or distort Indian drug use. A major project goal is to provide the same epidemiological framework for Indians as is now available for non-Indians. Regular surveys will chart drug use of 7th-12th graders in a sample of tribes stratified to be representative of Indian youth living on reservations. Drug use of very young children will also be studied in a further sample of 4th-6th graders. Marijuana use has become so widespread among young Native Americans that nine out of ten try it and 81% of them continue using it. This phenomenon will be examined indepth, including early involvement, present marijuana using behaviors and contexts, use in conjunction with other drugs, attitudes, perceived reasons for use, and beliefs about consequences of marijuana use. Indian youth not only use every drug more heavily than non-Indians, but they get involved at younger ages. Use of drugs by younger Indian children and the relationship of the age of early involvement to later drug use will, therefore, be studied. Adolescent drug use occurs in patterns or syndromes. A typology for classifying these styles or types of drug use has been developed and will be further studied during this project. The typology also provides a criterion for studies of drug use correlates. Our prior projects have validated, on samples of Indian youth, a wide variety of measures of potential correlates, including personality, attitudes, behaviors, family and peer influences and cultural identification. These, and new measures, will be evaluated using multivariate and path analyses to predict styles and types of drug involvement. Extensive reporting procedures will relay survey results to specific survey sites, to agencies serving Indians, and to Indian policy and advisory boards.